330 ATMOSPHERE IN RELATION TO HUMAN LIFE AND HEALTH. 



the organism on moisture in the air, on temperature of the air, on dark- 

 ness or light. The effect of belts of trees, walls, and muslin screens 

 in breaking its potency. The effect of dried air, as in a room with a 

 fire, in enfeebling the organism and nullifying its power to infect. The 

 effect of ozone and of nascent oxygen upon it, and the effect of anti- 

 septics such as thymol, cinnamon, toluol, and aromatic vapors. 



Inquiry into the infective power, if any, of malaria from person to 

 person through the air, a few instances having been recorded. 



CHOLERA. 



The extent to which cholera may be regarded as endemic in parts o± 

 India and other countries, the nature of the soil over which air is 

 infected, the most favorable amount of aeration and moisture of the 

 soil, the atmospheric conditions most favorable to its growth and to 

 its invasion of the air and of persons. The atmospheric conditions 

 most favorable to its extension over Europe and America, and the 

 special precautions needed to prevent the transport of the poison in 

 such conditions. The possibility of a system of international warn- 

 ings of the prevalence of the epidemic at any centers and of forecasts 

 of seasons or types of weather in connection with its probable spread. 

 The experimental use of some liquid, such as crude petroleum, for block- 

 ing the pores of earth where cholera is endemic, and preventing the 

 emission of germs into the air. The effect of cultivation of various 

 moisture absorbing and evaporating plants and trees in endemic areas. 



YELLOW FEVER. 



The transmissibility of yellow fever through the air from person to 

 person and how far, and its dependence on moisture, temperature, 

 wind, and other conditions of the air. The character of soil and sur- 

 face on which the microbe develops, the aeration of soil, etc., and the 

 possibility of checking its growth and emission into the air by spray- 

 ing with petroleum or some viscous disinfectant or antiseptic. Since 

 yellow fever germs seem to be aerobic and to grow largely on surfaces, 

 the treatment of street surfaces, walls, ships, harbors, etc., in this way 

 seems promising. 



THE PLAGUE, TYPHUS, TYPHOID, AND PNEUMONIA. 



The extent to which the plague, typhus, typhoid, and pneumonia are 

 severally capable of passing through and infecting in outside air, and 

 also confined air. Their dependence on infected soils and surfaces, 

 and on aerated or nonaerated soils; on atmospheric conditions, espe- 

 cially temperature and moisture, and on the seasons. Their depend- 

 ence on human habits and previous life, whether mostly in bad or in 

 fresh air. The influence of breath poisons on the growth and spread 

 of typhus, and of drain or sewer air and gases on animal and human 



